Soft microprocessor

A soft microprocessor (also called softcore microprocessor or a soft processor) is a microprocessor core that can be wholly implemented using logic synthesis. It can be implemented via different semiconductor devices containing programmable logic (e.g., ASIC, FPGA, CPLD), including both high-end and commodity variations.[1]

Most systems, if they use a soft processor at all, only use a single soft processor. However, a few designers tile as many soft cores onto an FPGA as will fit.[2] In those multi-core systems, rarely used resources can be shared between all the cores in a cluster.

While many people put exactly one soft microprocessor on a FPGA, a sufficiently large FPGA can hold two or more soft microprocessors, resulting in a multi-core processor. The number of soft processors on a single FPGA is limited only by the size of the FPGA.[3] Some people have put dozens or hundreds of soft microprocessors on a single FPGA.[4][5][6][7][8] This is one way to implement massive parallelism in computing, and can likewise by applied to in-memory computing.

A soft microprocessor and its surrounding peripherals implemented in a FPGA is less vulnerable to obsolescence than a discrete processor.[9][10][11]